I attached a picture with the black piece circled. I have no clue what it is but when my car gets up to temp its starts to let water out the top along with steam. Can someone tell me what the heck it is so i can replace it or fix it.

 

It's the heater diverter valve. The vacuum line on the top runs to the heater controls - when you have the slide set to WARM the diverter valve opens and allows hot coolant to circulate through the heater core, when slid to COLD it closes and the coolant bypasses the heater core.

Part No. 74805 at Advance Auto, $16.99

 

I think you have in backwards...flows hot water all the time execpt..when set to MAX A/C...it closes and doen't allow hot water to the heater core for max cooling.

 

ok so why is it letting coolant out and steam?

 

Because it's broke - it's just plastic, coolant is HOT, heat kills plastic.

 

I think he's right honestly.

It works off of the cold/warm control if I'm not mistaken.

 

Yeah that's what it is. I hate those damn things. I keep one in the back of my car. plastic gets brittle and breaks. usually have to change mine once every 2 years.

 

The A/C Vent Heat Defrost lever has the vacuum control valve connected to it, so when you change from the different settings it controls where vacuum is sent. The temp lever only controls the "Blend Door" that blends either outside air or A/C air and heater air

Set your A/C to Max
drive your car and let the air get cool.
put the temp setting to full warm

All that should come out of the vent is the temp of the air circulating inside the cabin

then set the A/C to Norm or Bi-level
Your temp out of the vents will get warm
If your system works any other way than that, your system is not functioning properly